Vibration generator

ABSTRACT

Vibratory thrust is generated by a rotating crankshaft and controlled orbital movement of a single weight pivoted to the crankpin of the crankshaft. As the crankshaft rotates the center of gravity of the weight moves back and forth on a vector through the crankshaft axis. The direction of the vector is adjustable within a substantial angular range about the crankshaft axis.

[ June 18, 1974 United States Patent [191 ()pderbeck 404/102 XWaschulewski................. 404/117 X k S w h C s [5 VIBRATIONGENERATOR 3,274,907 9/1966 Haage 75 Inventor: Rudolph G. Opderbeck, NewBerlin, 7/968 Wis. 3,616,703 Assignee: Wacker Corporation, Milwaukee,

Wis.

Primary Examiner-Nile C. Byers, Jr. Attorney, Agent, or Firm-James E.Nilles [22] Filed: Apr. 30, 1973 ABSTRACT 211 Appl. No.: 355,580

Vibratory thrust is generated by a rotating crankshaft and controlledorbital movement of a single weight pivoted to the crankpin of thecrankshaft. As the crankshaft rotates the center of gravity of theweight moves back and forth on a vector through the crankshaft axis. Thedirection of the vector is adjustable M 2 4mmm M ZM u m m m u 4 :M7 m Mm0 6 m Mm m &7 "m M L316, mm s m UhF within a substantial angular rangeabout the crankshaft axis.

References Cited UNITED STATES PATENTS 1,894,408 MacKenzie 404/117 2Claims, 9 Drawing Figures PATENTEBJun 18 1974 saw 1 or 4PATENTEDJIINIBIHH 3.817546 SHEEI 2 (IF 4 1 VIBRATION GENERATORBACKGROUND OF THE INVENTION The invention has to do with vibratoryequipment such as ground tampers, rammers, concrete vibrators, screensand other apparatus of that general category. More specifically, theinvention is concerned with a mechanism for generating the workingvibrations of the equipment.

In vibratory apparatus of various kinds it has heretofore been commonpractice to use excentric weights on rotating shafts to produce thedesired vibrations. In some of such previously known apparatus two ormore rotating excentric weights were arranged to rotate in apredetermined phase relation to each other in order to develop adominant reciprocating thrust force in a predetermined direction. Also,attempts have been made to obtain the same result with only one rotatingexcentric weight, but such one-weight vibration generators as heretoforeconstructed have not been entirely satisfactory in several respects,particularly in the matter of minimizing undesirable thrust componentsand utilizing driving power at maximum efficiency.

SUMMARY OF THE INVENTION The invention provides an improved one-weightvibration generator wherein an orbiting weight member is arranged insuch a manner that it will produce a vibratory thrust force in thedirection of a vector which extends through the central orbit axis ofthe weight member.

The improved vibration generator embodying the invention furtherincludes provisions for adjusting the vector of the thrust force withina substantial angular range about the central orbit axis of the weightmemher.

The invention further provides an improved vibration generator of theabove mentioned character which involves relatively few and simplestructural components, and whose overall weight may be kept low withoutsacrifice of strength and reliability. This is especially important withsome of the hand held tools.

A further feature of the improved vibration generator embodying theinvention is the provision of a driving mechanism for the orbitingweight member which is readily adjustable so as to progressively changethe position the thrust vectors from a forwardly inclined positionthrough a vertical position into a rearwardly inclined position, andvice versa.

A further feature of the improved vibration generator embodying theinvention is the absence of thrust forces other than those acting in thedirection of the angularly adjustable thrust vector, and the consequentoptimization of the machine performance and overall efficiency.

A further feature of the vibration generator embodying the invention isa reduction of operating noise and a decreased transmission of vibratoryforces to the engine due to the absence of side forces.

A further feature of the improved vibrating mechanism embodying theinvention is the provision of a housing which completely seals theorbiting weight member and its associated drive mechanism against theingress of dust and other environmental foreign matter.

When used on some apparatus such as rammers, the vibration generatorembodying the invention may be directly connected to the exteriorworking part, and no seals will be needed for the connections.

The foregoing features and advantages of the invention will become morefully apparent from the following description of a preferred embodimentwith reference to the accompanying drawings.

DRAWINGS FIG. 1 is a perspective view of a compactor having a vibrationgenerator incorporating the invention;

FIG. 2 is a perspective detail view of an adjusting mechanism for thevibration generator shown in FIG.

FIG. 3 is an enlarged perspective view, partly in section, of thevibration generator shown in FIG. 1;

FIG. 4 is a vertical longitudinal section of the vibration generatorshown in FIGS. 1 and 3, parts shown in FIG. 4 being shown in arotatively displaced position with reference to FIG. 3;

FIGS. 5-9 are diagrammatic views illustrating various operating phasesof the vibration generator shown in FIGS. 1, 3 and 4, the views of FIGS.5-9 being taken in the direction of the arrows E-E in FIG. 4.

DETAILED DESCRIPTION The compactor shown in FIG. 1 comprises a rigid,unitary tamping body 1; a vibration generator 2 mounted on top of andrigidly secured to the tamping body 1; an internal combustion engine 3and accessories supported by the body 1; a belt drive 4 transmittingdriving power from the engine 3 to the vibration generator 2; a U-shapedhandle bar 6 for manipulation by an operator walking behind thecompactor; and an adjusting lever 7 on the handle bar for controllingthe direction in which vibratory thrust is exerted by the vibrationgenerator 2 upon the tamping body 1, as will be explained more fullyhereinbelow.

Referring to FIGS. 3 and 4, a generally cup shaped housing section 8 isclosed by an end cover 9, and the journal 10 of a crankshaft 11 isrotatably supported in a bearing opening of the cover 9 by means ofaxially spaced antifriction bearings 15 and 13. The crankshaft 11 has acrankpin 12 which extends partway into the housing space between theclosed end of the cut section 8 and the end cover 9. An orbiting weight13 within the cup section 8 comprises a sector shaped body portion 14(FIG. 3), a central radial prong l6, and two radial prongs l7 and 18 atthe axially opposite sides of the mounting prong l6 and spaced therefromby recesses 19 and 21, respectively. The radial prongs l6 and 17 areaxially apertured to accommodate the crankpin 12 of the crankshaft 11,and a needle bearing 22 is seated on the end of the crankpin 12 andfitted into the axial aperture of the mounting prong 16 so as topivotally connect the weight member 13 with the crankpin 12.

At the side of the weight member 13 next to the bottom of the cup shapedhousing member 8 a pinion 23 is rigidly secured to the radial prong 18in axial alignment with the crankpin 12 of the crankshaft 11. A stubshaft 24 of the prong 18 extends into a central axial bore of the pinion23, and a key 26 and a cap screw 27 secure the pinion 23 in axially androtatively fixed position to the weight member 13. The pinion 23comprises a smooth cylindrical collar 28 adjacent to prong 18 of theweight 13, and a circumferential series of external gear teeth 29 at itsaxially outer end. The purpose of the collar 28 is to provide for thetransmission of centrifugal force from the weight member 13 to anannular guide track 30 within the housing section 8. A similar collar 31is secured to the radial prong 17 of the weight member 13 forcooperative engagement with an annular guidetrack 32 within the housingcover 9. The cylindrical inner surfaces of the guidetrack 30 and 32, andthe cylindrical outer surfaces of the collars 28 and 31 arediametrically so proportioned that the collars will roll along the guidetracks as the crankshaft 11 is rotated in its bearings and 13. To thatend the effective diameters of the guide tracks 30 and 32 are made twiceas large as the effective diameters of the collars 28 and 31,respectively.

The gear teeth 29 of the pinion 23 mesh with gear teeth 33 of aninternal ring gear 34 which is rotatably seated in a cylindrical recess36 of the housing section 8. A cylindrical outer surface and a radialend face of the ring gear 34 bear against cylindrical and radial innersurfaces, respectively, of the recess 36, and a stub shaft 37 integrallyformed with the ring gear 34 extends through a central axial aperture 38of the housing section 8. A seal 39 surrounding the stub shaft 37 isretained in the aperture 38 by a snap ring 41, and a similar seal 42surrounding the crankshaft journal 10 is retained in an axial aperture43 of the end cover 9 by a snap ring 44.

In the assembled condition of the mechanism as shown in FIG. 4, the ringgear 34 is axially aligned with the crankshaft journal 10. Also, thering gear 34 is prevented from rotating about its axis by suitable meansnot shown in FIGS. 3 and 4, but illustrated by way of example in FIGS. 1and 2.

The ring gear adjusting means illustrated in FIGS. 1 and 2 comprise adouble armed rocker 46 (FIG. 2) which is keyed to the stub shaft 37 ofthe ring gear 34; and cables 47, 48 which are attached to the oppositeends of the rocker. The cables 47, 48 connected with the hand lever 7 inFIG. 1 in such a manner that forward adjustment of the lever 7 from anupright position in the direction of arrow A in FIG. 1 swings the rocker46 in FIG. 2 from a vertical position in the direction of arrow A, andso that rearward adjustment of the lever 7 in FIG. 1 from its uprightposition in the direction of arrow B swings the rocker 46 in FIG. 2 fromits vertical position in the direction of arrow B.

As will presently be explained with reference to FIGS. 5 to 9, thevibration generator 2 when driven by the engine 3 functions to produce astraight up and down vibratory thrust when the lever 7 and rocker 46 arepositioned vertically. In that case the apparatus shown in FIG. 1 willvibrate up and down but will be subjected to no forward or rearwardpropelling force.

Alternately, when the lever 7 and rocker 46 are moved to forwardlyadjusted positions in the directions of arrows A and A, respectively,the vibration generator 2 produces a downwardly and rearwardly directedvibratory force which in addition to its compacting ef fect tends tomove the apparatus forwardly.

On the other hand, when the lever 7 and rocker 46 are moved torearwardly adjusted positions in the direction of arrows B and B,respectively, the vibration generator 2 produces a downwardly andforwardly directed vibratory force which in addition to its compactingeffect tends to move the apparatus rearwardly.

FIGS. 5, 6 and 7 show the ring gear 34 in the rotatively adjustedposition in which it is held when the lever 7 (FIG. 1) and the rocker 46(FIG. 2) are positioned vertically. The pitch diameter PD of the ringgear 34 is twice as large as the pitch diameter pd of the pinion 23; andthe radial spacing of the center of gravity CG (FIG. 4) of the weightmember 13 from the axis of the crankpin 12 of the crankshaft 11 is equalto the pitch radius of the pinion 23. The gear ratio of the pinion 23 tothe ring gear 34 is one to two.

In FIG. 5 the point of mesh of the pinion 23 with the ring gear 34, andalso the center of gravity CG of the weight 13 are located on a verticalline through the crankshaft axis X. Centrifugal force of the weight 13in this condition of the mechanism is a maximum and effective in thedirection of the vertical vector V1.

In FIG. 6 the crankpin 12 has moved anticlockwise degrees from its FIG.5 position, and the center of gravity CG of the weight 13 has movedstraight down upon the crankshaft axis X. In this condition of themechanism the weight 13 exerts no vibratory centrifugal force in anydirection.

In FIG. 7 the crankpin 12 has moved anticlockwise degrees from its FIG.5 position, and the center of gravity CG of the weight 13 has movedstraight down from the crankshaft axis X to the point of mesh with thepinion 23 with the ring gear 34. In this condition of the mechanismcentrifugal force of the weight 13 is again a maximum but now effectivein the direction of the vertical vector V2 which is reversed withrespect to the vector V1 in FIG. 5.

Continued anticlockwise rotation of the crankpin 12 from the FIG. 7position through the remaining 180 of a full revolution, returns thecenter of gravity CG of the weight 13 straight upward through thecrankshaft axis X into the FIG. 5 position, and during such returnmovement of the center of gravity the centrifugal force of the weight 13progressively decreases from maximum (FIG. 7) to zero (FIG. 6) and thenincreases from zero (FIG. 6) to maximum (FIG. 5). It is thus evidentthat when the lever 7 (FIG. 1) and the rocker 46 are positionedvertically rotation of the crankshaft 11 at high speed either clockwiseor anticlockwise generated a strong vibratory straight up and downthrust upon the tamper body 1 without undesirable side components whichwould impair the operating efficiency of the apparatus and unnecessarilyincrease its power consump tion. The vibratory thrust forces of theorbiting weight 13 are transmitted to the vibrator housing 8, 9 by thecollars 28 and 31 rolling on the guide tracks 30, 32, thus insuringsmooth and quiet operation of the vibration generator. Lubricant withinthe housing 8, 9 will reach not only the guide tracks and gear teeth,but will also be supplied to the needle bearing 16 through the recesses19 and 21 between the prongs 16, 17 and 18 of the weight 13.

FIG. 8 shows the ring gear 34 rotated clockwise through an angle a fromthe position in which it is shown in FIG. 5. Such clockwise movement ofthe ring gear 34 through the angle a due to the meshing engagement ofthe ring gear teeth with the pinion teeth will put the center of gravityCG of the weight 13 on a line which extends through the crankshaft axisX at an angle of 90 0: relative to the horizontal. In operation, whenthe crankshaft 11 is rotated at high speed in either' direction, thecenter of gravity CG of the weight 13 moves back and forth on a straightline through the crankshaft axis X as explained hereinbefore withreference to FIGS. 5-7. However, in the case of FIG. 8, that line isinclined downwardly and rearwardly relative to the horizontal, and thethrust vector V2 will, in addition to its compacting effect, subject theapparatus shown in FIG. 1 to a propelling force in a forward direction.

The foregoing explanations with reference to FIG. 8 analogously apply toFIG. 9 which shows the ring gear 34 rotated anticlockwise through anangle [3 by adjustment of the lever 7 in FIG. 1 in the direction ofarrow B. In FIG. 9, the vibratory thrust acts on a line which extends atan angle 90 ,8 relative to the horizontal. The thrust vector V2 isdirected downwardly and forwardly and, in addition to its compactingeffect, subjects the apparatus shown in FIG. 1 to a propelling force ina rearward direction.

In a vibratory apparatus such as the compactor shown in FIG. 1, thedirection of vibratory thrust should preferably be variable with afairly broad angular range such as ll50 so that the apparatus may beoperated most efficiently under all working conditions and bemanipulated conveniently in close quarters. The herein disclosedvibration generator readily lends itself to angular adjustment of theline of vibratory thrust within the desired broad range simply by rotaryadjustment of the ring 34.

I claim:

1. A vibratory apparatus comprising a tamping body, a vibrationgenerator housing rigidly secured to said tamping body; a crankshafthaving a journal and a crank pin within said housing, bearing means insaid housing supporting said crankshaft journal for rotation on ahorizontal axis; a weight member eccentrically connected with said crankpin in rotatable relation thereto; a pinion in axial alignment with saidcrank pin non-rotatably secured to said weight member; an internal ringgear in mesh with said pinion rotatably mounted within said housingcoaxially with said crankshaft journal; and adjusting means for saidring gear operable to selectively secure said ring gear in differentrotatively adjusted positions.

2. A vibratory apparatus as set forth in claim 1 wherein said adjustmentmeans comprise a back and forth movable hand lever, and connecting meansbe tween said hand lever and said ring gear operable to rock said ringgear back and forth about its axis in response to back and forthmovements, respectively, of

said hand lever.

1. A vibratory apparatus comprising a tamping body, a vibrationgenerator housing rigidly secured to said tamping body; a crankshafthaving a journal and a crank pin within said housing, bearing means insaid housing supporting said crankshaft journal for rotation on ahorizontal axis; a weight member eccentrically connected with said crankpin in rotatable relation thereto; a pinion in axial alignment with saidcrank pin non-rotatably secured to said weight member; an internal ringgear in mesh with said pinion rotatably mounted within said housingcoaxially with said crankshaft journal; and adjusting means for saidring gear operable to selectively secure said ring gear in differentrotatively adjusted positions.
 2. A vibratory apparatus as set forth inclaim 1 wherein said adjustment means comprise a back and forth movablehand lever, and connecting means between said hand lever and said ringgear operable to rock said ring gear back and forth about its axis inresponse to back and forth movements, respectively, of said hand lever.